UPS Label size when generated via Zoho

UPS Label size when generated via Zoho

We've integrated UPS with Zoho inventory.

When creating and downloading the shipping labels they are created in a larger paper size. I'd like them to be generated to print on a 4x6 printer.

Zoho have told me I need to do this within our UPS portal.
UPS says this needs to be completed with Zoho.

Where is the setting to define the label size within Zoho?
It's not under Templates as Shipping Lables does not exist.